Cable contact



' April 15, 1941 E. R. GoLDFlELD CABLE CONTACT Filed July 12, 1940 I l24 19ML 19g FIG-2. v

FIG-5 Flc-4 FIG-l INVENTQR EDWIN R. GOLDFIELD A Patented Apr. 15g, 1941CABLE ooN'racvr Edwin R. Goldileld, University Heights, Ohio, as-

signor to Picker X-Bay Corporation. Waite Manufacturing Division, Inc.,Cleveland, Ohio, a corporation of Ohio Application July 12, y1940,Serial No. 345,080 z claims. w1. 17a- 324) 'I'his .invention relates toimprovements in electrical cable connectors and particularly toimprovements in means for connecting heavy electrical cables :to high`voltage equipment such as X-ray Vtubes and the like.

Electrical connections to high voltage equipment such as X-ray rtubesinclude very heavy cables sometimes almost an inch in diameter carryingseveral conductors which are very heavily insulated because of the highvoltages carried. For instance it is com-mon in connections to X-raytubes to use a cable carrying .three conductors, one for the tube anodeor cathode, one for the lament and one for 'the return line. Thesecables are connected to tube equipment which must necessarily bemanipulated in the ordinarycourse Yof operations. Such manipula- Y tionrequires movement of the connecting cables which, because of their heavycharacter, arevnot easily distorted. It is very desirable therefore toprovide cable connectors permitting a twisting .or rotation of the'cables in their sockets without disturbing the electrical connections.It is also important that such contacts be adapted to carry the highvoltages used in a safe manner and tional view` taken along .the line 55 of Fig. 4; while Fig. 6 is a sectional view of one of the contactmembers of Figs. 2 and 3.

In the drawing it will .be understood that the cable I is a cable of theusual character found inX-ray equipment carrying three electricalconductors Il, I2 and i 3, one of which is adapted Ito carry ythe tubecurrent. one for the lament current and one for the return line. Suchcurrents are of the order of 25,000 peak volts or higher. Thesesamecurrents are carried on to the equipment served by .the connections I4,I5 and I6, leaving the other end of the device here disclosed. It willbe understood that the conductors extending beyond the points I4, I5 andI6 are generally oil immersed and the design of my improved connectortakes this feature into account.

My novel connector device includes an inner `cylindrical sleeve I1 andan outer cylindrical particularlyto prevent spark-over and corona'effects when the high voltages are used in humid atmosphere or at high"altitudes.

One of the objects of .the present inventionis to provide a novel meansfor connecting electric cables comprising coacting sets ofconcentrically arranged intertltting contact members permitting relativerotation betweenl -the movable contact members connected with theelectrical cable and `the fixed contact members on the X-ray tubeequipment.

Another object of the present invention is to provide a very-.ruggedconnection of electrical cables with high voltage equipment permitting a.twisting of the cables and at the same time rendering any spark-overpractically impossible and housing .the parts in such a manner that theyare sufciently ruggedto stand much abuse even to the extent of beingdragged through mud and water as is sometimes necessary with armyequipment or other emergency use of X-ray apparat/us.

Other objects and advantages of the present invention will be apparentfrom the accompanyingspeciiication and drawing and the essentialfeatures will he set forth in the claims.

In .the drawing, Fig. 1 is an elevational view of pose which'will -belater described.

vat I9.

sleeve I8 having an overall length in the present embodiment of fromfour to six inches for a pur- The clearance betweenthe outside diameterof sleeve I1 and the inside diameter of sleeve I8 is .lust suilione endof the lcylinder I'Ia and passalong sub.

stantially -the entire length thereof to the free end where theelectrical conductors are secured -to a set of contact members indicatedgenerally The contact members are secured to a heavy sheet of insulatingmaterial 20 which closes the end of the cylinder 11a and all of thevfree space within the cylinder Ila and surroundingv the cable and itsconductors indicated generally at ZI is filled with a plastic insulatinfmaterial which lflows readily when heated and stiiens upon cooling. Thiscompletely seals and lls the entire space within the cylinder |1a up tothe member 20. A spring strip of corrugated metal 22 engages in`recesses Z3 on the inner face of cylinder 11a so as to serve to positionthe member 20.

Referring nowto the set of contact members indicated generally at I9,this comprises annular substantially rigid contact members Isa, Hb andlSc concentrically arranged. Each of the contact members has portionspassing .through the member 2l and bent down on .the inside thereof soas to firmly hold 'the contact members'in place. '.I'he conductors Il,I2 and I3 are soldered to their 'housing associated contact members soas to form .permanent connections. The contact members havelongitudinally extending slots as indicated at 24' so as lto provide aslight yielding effect the better to frictionally engage .fthe coactingset of contacts carried by the sleeve I8. A detailed arrangement of thecontact member ISb is shown in Fig. 6 where the longitudinally extendingslot 24 is extended in T-form as indicated at 24a so as A.to givegreater iiexibility at fthe free ends of the contact member.

'Ihe sleeve i8 is threaded as indicated at Ia for attachment to an X-raytube or to an oil immersion tank carrying the associated equipment. Thesleeve also has provided integrally therewith a transversely extendingwall IBb which carries centrally thereof a set of contacts indicatedgenerally at 25.

The set of contacts 25 comprises three substantially annularcontactmembers 25a, 25h and 25e concentrically arranged preferably insuch a manner that they lie radially outside of the respective contactmembers in the set I9. Referring to the detailed arrangement of Figs. 4and 5,

the member 25e has a truncated conical surface r 26 which engages acomplementary surface of the wall |81, these surfaces being tightlypulled together by a nut 21 threaded on the member 2B, thus holding inplace the connector member I5, a washer 28 and a gasket 29. A spacer 30of insulating material having truncated conical shape spaces the members25o and 25h. The member 25h is heldassembled by a nu-t 3I which holds inplace the connector member I6 and a sheet of insulating material 32. Aspacer 33 of insulating material having ltruncated conical formseparates the contact members 25h and 25a. The

member 25a has a threaded stem 34 to the lower end of which is attacheda nu-t 35 which secures in place the connector member Il and a sheet ofinsulating material 36. It will be noted that the set of contact membersassembled at 25 together with the wall I8b sealsone end of the shell I5against liquid' leakage from the oil immersion compartment generallyconnected to the threads Ilia.

When rthe parts are assembled as shown in Fig. 1, the contact members ofthe set I9 frictionally engage and overlap the contact members of theset 25 with the corrponding membersof d the set 25 lying radiallyoutward of the members of the set I9. The cylinder ila then provides askirt I'Ic at its inner or free end which engages tightly against thewall 68D, thus overlapping and both sets of contacts and practicallypreventing any spark-over from them. In any case spark-over travellingfrom the set of contacts 25 toward the cable I0 would have to traveldownwardly as viewed in Fig. 1 for the exposed length of contact member25c and thenupwardly along the outside of the cylinder Ila. Thus anoverlapping of the parts IIc and 25e, by for instance three-eighths ofan inch, will compel any sparkover to traverse a path of more thanthreequarters of an inch, at the same time relative rotation of thecontacts I9 and 25 may occur freely without any strains on the cable I0.

The arrangement of the concentric annular contacts I9 and 25 provides amuch greater area of coacting contacting surfaces than is found in thecustomary interengaging prongs of the prior art.

What I claim is:

y1. An electric cable connector comprising inner and outer sleeves ofrigid insulating material adapted to have a sliding t one within theother, the clearance between the outside diameter of said inner sleeveand the inside diameter of said outer sleeve being just sufficient topermit sliding movement between the sleeves, said sleeves having alength of approximately four or iive inches. a set of relatively xedcontact members, said outer sleeve Ihaving a transverse wall near oneend supporting said set of contact members centrally of said sleeve withthe contact members extending into the sleeve from said wall, said walland set and mounting thereforclosing and sealing said sleeve end,electric cable conductors enterlngkat one end of said inner sleeveandextending through substantially its entire 4length to the other or freeend thereof, asecond set of con tact members connected to said cableconductors, plastic insulating material sealing said conductors and saidsecond set of contact members within said inner sleeve, leach of saidsets of contact members comprising a plurality of concentric membersinsulated from members in the same set, said sets interfltting andoverlapping when said sets are in engagement with the members of therelatively xed set respectively radially outside` the members of thesecond set, and the free end of said inner sleeve surrounding theoutermost contact member of said fixed set and forming a continuousskirt engaging said wall when said sets of contact members are inopera-tive engagement.

2. An electric cable connector comprising male and female members ofrigid insulating material, said members being of intertlttingcylindrical form "with just suiiicient clearance between the outsidediameter of the male member and the inside` diameter of the femalemember to permit axial sliding movement between them, two frictionallyengageable sets of `concentrically `ar ranged contacts, the contacts ofeach set being electrically insulated from each other, said sets beingpositioned rigidly one on each of said members in position to be engagedonly when said members are in intertting engagement with one memberfully within the other, whereby one of said sets of contacts'is at theinner end of said male member, an electrical cable integrally connectedwith the outer end of said male memberl and having an outer sheath oflow potential, said cable having internally thereof a plurality ofconductors adapted to carry a current of high potential of the order of25,000 peak volts, said conductors being integrally joined respectivelywith the contacts of that set positioned at the inner end of said malemember, and said male member being of such a length that there is atleast three inches between the set of contacts at the inner end of saidmale member and the nearest point of the outer sheath of said cable atthe outer end of said male member, whereby said cable and male membermay be rotated relative to the set of contacts on said female member andwhen said sets of contacts are engaged the spark-'over or corona effectsmust travel at least three inches from said contacts through the limitedclearance space between said members to reach the nearest exposed pointon said cable.

EDWIN R. GOLDFIELD.

